Clown Doctor Karen Bell – known to children as Dr Jemima Jamjuggle – said she and her colleagues play a unique role in aiding recovery.

Karen, of Dipton, County Durham, said: “There are scientific studies that have shown the positive effects of laughter.

“It can oxygenate the blood and that can play a role in a patient’s wellbeing, so the benefits can last for longer than just the length of a clown doctor’s visit.”

The international movement was inspired by American physician Dr Hunter “Patch” Adams, who travels to hospitals around the world dressed as a clown in an effort to bring humor to orphans, patients, and other people.

His life was portrayed in the film Patch Adams by actor Robin Williams - whose suicide two weeks ago shocked the world.

But TIN Arts, an arts development company which manages the region’s Clown Doctors, said they could do so much more with more cash.

“The level of funding we get only enables us to provide the service for a just half a day at the Great North Children’s Hospital, and that’s not nearly enough,” said Nuritza Daghlian, of TIN Arts.

“The demand is certainly there, but we simply cannot meet it at the moment, which means many poorly children are missing out.”

The programme at the GNCH is funded by the Children’s Foundation, whilst CHUF funds the programme at the Freeman Hospital.

One couple who know all about the benefits of the programme are teachers Louise Gibson and Scott Sweeney, of Whitley Bay.

Robin Williams as clown doctor Patch Adams in the film of the same name

Their son Austin, five, underwent a bone marrow transplant last year after a two-year battle with cancer that began when he was diagnosed with acute lymphoblastic leukaemia at the age of two.

Louise, 41, said: “Austin has had quite a few visits from the Clown Doctors and it has always had a positive impact on his wellbeing.

“When you are living on the Oncology Ward, every day you are hoping for some good news as the situation can be extremely stressful for everyone.

“To have the smiling, friendly faces of the clown doctors appear and have some jokes, silly songs and tricks, is fantastic escapism.

“Especially when your child smiles for the first time in ages; that is invaluable to a parent.”

Louise added: “After Austin’s Transplant we lived at home in isolation and he wasn’t allowed to see, let alone play with, anyone his age because the risk of infection was so great.

“On one special occasion, the clown doctors visited us. Two of them arrived on unicycles and they started throwing a diabolo higher than our house and Austin watched from the window whooping with laughter, it was amazing.

“In a situation like that, anything that puts a smile on your child’s face – and yours – has to be worth it. Obviously treatment and medication come first, but it’s true what they say...a real good laugh can be a tonic.”

Unlike the original Hunter ‘Patch’ Adams, who now lives in Urbana, Illinois, the region’s eight-strong team of Clown Doctors are not medically trained.

They are performing artists with a range of skills including puppetry, street theatre, movement and improvisation, chosen for their ability to empathise and engage with sick children.

Hospital ‘play specialists’ identify children they feel would benefit from a visit then brief Clown Doctors on their condition and what stimulus they are most likely to respond to.

Karen added: “It’s awful to see a child in pain and discomfort, but at the same time hugely rewarding if you can bring a smile to their face.

“The feedback we get from hospital staff tells us that what we do is not simply an isolated intervention – the repercussions carry on through the week, with children talking about the experience and often re-enacting some of our interactions.

“And they look forward to us coming back, so that lifts their spirits too. That’s why I’m convinced what we do is really valuable, even though the outcomes are not easily measured.

“We’re grateful to the Children’s Foundation for the backing they give us, but unfortunately their funds are limited.

“If there was more money coming in, we could do much more. The demand is certainly there.”